1. Field of the Invention
This invention relates to an improvement in an automatic film loading device which loads sheet film into a cassette.
2. Description of the Prior Art
In an X-ray photographic system using a cassette, it is the customary practice to manually load a sheet of film into a cassette inside a dark room, and then return to the dark room to remove the exposed film from the cassette for subsequent development after the X-ray photograph has been exposed. To take another X-ray photograph, it is necessary to manually load a fresh sheet of film into the cassette and the above sequence of operations must be repeated. The applicant of the present invention previously devised a sheet film loading and unloading device which eliminated the necessity of the operations inside the dark room and made it possible to load and unload the film in the light, and filed the invention as Japanese Utility Model Application No. 158186/1980. In an X-ray photographic system using this prior art device, after the sheet of film inside the cassette is removed from the cassette in the light, a fresh sheet of film is loaded, the lid of the cassette is closed and the cassette is then discharged from the system. Though the prior art is advantageous in that it frees the operator of the system from the need of operations in the dark room, it involves the problem that the cassettes discharged from the system are always discharged with their lids closed. In other words, there is no problem so long as there really is a sheet of film in the cassette, but if the sheet of film is not loaded into a cassette for some reason, the cassette is still discharged with its lid closed so that the operator of the system is always uncertain as to whether or not a fresh film has actually been loaded into a cassette discharged with its lid closed.